The present invention relates generally to communication networks, and more specifically, to a scalable, loop-free ring topology, which does not require control plane messaging, and associated protocols.
Spanning-Tree Protocol (STP) is a Layer 2 protocol designed to run on bridges and switches. The STP specification is defined in IEEE 802.1d. The main goal of STP is to make sure that a loop situation does not occur when there are redundant paths in a network. STP accomplishes this by disabling network loops and providing backup links between switches or bridges. STP allows devices to interact with other STP compliant devices in the network to ensure that only one path exists between any two stations on the network. If STP or a similar protocol is not present in a redundant topology network, switches may endlessly flood broadcast packets to all ports (i.e., broadcast storm). When multiple copies of a frame arrive at different ports of a switch, MAC entry instability in a Filtering Database may occur.
STP, RSTP (Rapid Spanning Tree Protocol) (defined in IEEE 802.1W), and other topology distribution protocols have partially solved the loop problems described above. However, these solutions are not scalable when sub-second convergence times are required. Furthermore, these protocols do not utilize bandwidth well (i.e., one link/port is always blocked) and are often very complex and result in additional hardware requirements.
There is, therefore, a need for a scalable, loop-free, ring topology which optimizes available bandwidth utilization without the overhead complexity of control packets and associated protocols.